Skip to main content
Search type Search syntax
Tags [tag]
Exact "words here"
Author user:1234
user:me (yours)
Score score:3 (3+)
score:0 (none)
Answers answers:3 (3+)
answers:0 (none)
isaccepted:yes
hasaccepted:no
inquestion:1234
Views views:250
Code code:"if (foo != bar)"
Sections title:apples
body:"apples oranges"
URL url:"*.example.com"
Saves in:saves
Status closed:yes
duplicate:no
migrated:no
wiki:no
Types is:question
is:answer
Exclude -[tag]
-apples
For more details on advanced search visit our help page
Results tagged with
Search options answers only not deleted user 11260

Hamiltonian systems, symplectic flows, classical integrable systems

10 votes

Which paper is the "Taubes trick" from?

The established reference (see for example arXiv:0912.0651) to Taubes trick is C.H. Taubes, Seiberg Witten and Gromov invariants for symplectic 4-manifolds (2000). This book collects results from fo …
Carlo Beenakker's user avatar
3 votes

Does this distribution exist?

It seems your equation implies $\hat{W}(0,\mu_1)\hat{W}(0,\mu_2)=\hat{W}(0,\mu_1+\mu_2)$, which would mean that $\hat{W}(0,\mu)= e^{c\mu}$. This is not the Fourier transform of a valid marginal distri …
Carlo Beenakker's user avatar
0 votes

Goldman symplectic form vs Weil–Petersson symplectic form

The factor of four and why Goldman has a different factor is explained on page 6 of Generalization of a formula of Wolpert for balanced geodesic graphs on closed hyperbolic surfaces. A derivation with …
Carlo Beenakker's user avatar
2 votes

A geometric interpretation of the fractional Fourier transform

For the record, to answer Q2, let me write down the Mehler kernel for the square root of the Fourier transform, $$K(x,y)=(2\pi)^{-1/2}\sqrt{1-i}\exp\left[{\tfrac{1}{2} i \left(x^2+y^2-2 \sqrt{2} x y\r …
Carlo Beenakker's user avatar
14 votes

Applications of symplectic geometry to classical mechanics

V.I. Arnold's Mathematical Methods of Classical Mechanics is entirely based on the ideas and methods of symplectic geometry, such as the Birkhoff normal form, the Kolmogorov- Arnold-Moser theorem on t …
Stefan Waldmann's user avatar
3 votes

Is there a formulation of Huygens' principle using the language of algebraic geometry?

An analogue of the Huygens principle (including interference, so more precisely a Huygens-Fresnel principle) in superspace has been formulated by Gomes in arXiv:gr-qc/0602092. The formulation is used …
Carlo Beenakker's user avatar
70 votes

Is there a high level reason why the inverse square law of gravitation yields periodic orbit...

The gravitational or Coulomb potential has a "hidden" symmetry (hidden in the sense that it does not follow from the rotational symmetry). The resulting integral of the motion (the Runge-Lenz vector) …
Carlo Beenakker's user avatar
33 votes

The Planck constant for mathematicians

To build intuition for the Planck constant $\hbar$, which I understand is the purpose of the OP, I would start by noting that $\hbar$ is not a dimensionless number: it has dimensions of energy $\times …
Carlo Beenakker's user avatar
4 votes

Symplectic equivalent of commuting matrices

The symplectic counterpart of the fact that a family of commuting diagonalizable matrices is simultaneously diagonalizable is discussed in section 3.1 of On the diagonalizability of a matrix by a symp …
Carlo Beenakker's user avatar
2 votes
Accepted

Abstract stationary phase

the $a_i$'s are complex coefficients in the asymptotic expansion $a(h)=\sum_{i=0}^\infty a_i h^i$; a more explicit expression is given on page 275-276 of Guillemin and Sternberg:
Carlo Beenakker's user avatar
8 votes

What is the current status of the Arnold conjecture?

A recent (2017) overview of the status of Arnold's conjecture is given in The number of Hamiltonian fixed points on symplectically aspherical manifolds.
Carlo Beenakker's user avatar
4 votes

Non-Hamiltonian actions in physics

The master thesis Nonholonomic Dynamical Systems by Brett Ryland contains several examples of non-Hamiltonian systems from classical physics: the dynamics of a laser and the evolution of a gas flame ( …
Carlo Beenakker's user avatar
12 votes
Accepted

Why are Lagrangian submanifolds called Lagrangian?

This echos the 2017 comments, but since the question has now been bumped to the front page it might be helpful to give the actual source in Maslov's book [1]. [1] V.P. Maslov, Perturbation Theory …
Carlo Beenakker's user avatar
5 votes
Accepted

Moyal $\star$-product inverse?

The inversion is conveniently described in terms of the Fourier transform $$g(x,p)=\int dy\,e^{-iyp}G(x+y/2,x-y/2).$$ Then the composition $f(x,p)=g(x,p)\star h(x,p)$ is a matrix multiplication [1], $ …
Carlo Beenakker's user avatar
16 votes
Accepted

What is an "integrable hierarchy"? (to a mathematician)

An integrable hierarchy is another name for a system of commuting Hamiltonian flows. The word "hierarchy" is used because a countably infinite number of commuting flows is obtained recursively. [For t …
Carlo Beenakker's user avatar

15 30 50 per page